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The information in this section focuses on electrical circuits and the kind of devices that we can build using those circuits.


Electric Current:

The movement of electric current can be compared with a pipe full of water: If water is put in the pipe at one end, water will drip out of the other end almost immediately - It may appear that the water flows very quickly… but the drop that flows in has not moved very much from where it entered - the water flows out of the other end almost immediately, but the drop that flows out is not the same drop that flows in!

  • Electric current is the movement of electric charge.
  • Particles called electrons carry the electric charge.
  • The charge of an electron is negative*.
  • Some substances (called conductors) conduct very well, e.g. metals.
  • Other substances conduct zero or very little electric current, e.g. glass and most plastics.
  • Conductivity is based on the presence of mobile charge carriers in the conducting material.
  • Electric current is nearly as fast as the speed of light, whereas the average 'drift' velocity of an electron is slow.

* Previously people (wrongly) thought that positive particles serve as charge carriers. Due to this error, 'conventional current' flow is shown as moving in the opposite direction of the electrons (see diagram below):

Flow of electrical current

Figure 1: Direction of flow of electrons versus 'conventional current' flow (Source)

Introduction to The Internet of Things:

Why circuits and electrical devices will be even more important in the future:

According to ABI Research & Forbes: By 2020, the Internet of Things will generate 30 billion autonomously connected end points and $8.9 trillion in revenues. IDC predicts that in 2014 -2016 we will see new partnerships among IT vendors, service providers, and semiconductor vendors that will address this market. Again, China will be a key player: The average Chinese home in 2030 will have 40–50 intelligent devices/sensors, generating 200TB of data annually. http://www.forbes.com/sites/gilpress/2013/12/03/idc-top-10-technology-predictions-for-2014/#!

“We have a clear vision: To create a world where every object, from jumbo jets to sewing needles, is linked to the Internet” http://en.wikipedia.org/wiki/Internet_of_Things

Video: Dr Andy Stanford-Clark is a Distinguished Engineer and Master Inventor at IBM UK

He specialises in technologies which are helping to make the planet smarter, by analysing and reacting to data from remote sensors.

Circuit Links & Resources:

A simple interactive activity to build a circuit and see what happens:

To see static electricity at work, rub foot on carpet and open door!

“There are 10 types of people in the world: Those who understand binary and those who don't!” Anon

learn/circuits/home.txt · Last modified: 21/12/2016/ 17:34 (external edit)